Fluid-cooled terminal for a flexible electrical conductor



June 26, 1962 J. s. WREFORD- FLUID-COOLED TERMINAL FOR FLEXIBLE ELECTRICAL CONDUCTOR Original Filed April 16, 1956 INVENTOR. Jzfi 5. Wnezrd United States Patent 3,041,408 FLUID-COOLER) TERMINAL FOR A FLEXIBLE ELECTRICAL CONDUCTOR John S. Wreford, Franklin, Mich, assignor to Gar Wood Industries, Inc, Wayne, Mich, a corporation of Michigan Continuation of application Ser. No. 578,438, Apr. 16, 1956. This application Sept. 8, 1959, Ser. No. 838,731

3 Claims. (Cl. 174-19) 7 This invention relates generally to flexible electrical conductors, and more particularly to a fluid-cooled terminal for a flexible electrical conductor.

This application is a continuing application of my copending application, Serial No. 578,438, filed April 16, 1956, now abandoned.

Flexible conductors are often employed to electrically connect machines to a power supply when the machine must move relative to the power supply. Often a considerable amount of heat is developed at the terminals of a flexible conductor that cannot be dissipated by cooling devices provided for the equipment to which the conductor is electrically connected. As a result, the flexible conductor may be annealed or otherwise damaged, resulting in a relatively short operating life.

Prior attempts to cool the terminals of a flexible conductor were made by casting metal terminals with a cooling chamber adjacent a conductor socket into which the end portion of a flexible conductor was inserted and silver soldered. This expedient, while an improvement on uncooled terminals, was expensive to make, of relatively low thermal efiiciency because of the necessity of conducting heat through the terminal casting, and of relatively low electrical efliciency because of the resistance occurring at the junction between the conductor and the adjacent socket wall.

Accordingly, the broad object of this invention is to provide a fluid-cooled terminal for a flexible conductor that is of relatively high electrical and thermal efliciency because of improved mechanical and electrical contact between the strands of the flexible conductor and a cooling tube and outer shell of the terminal.

Another object is to provide a fluid-cooled terminal for a flexible conductor wherein cooling is accomplished by the flow of fluid through a tube imbedded or compacted in the strands of the flexible conductor at high mechanical pressure brought about preferably by deformation of an outer terminal shell so as to substantially prevent exposing of the contacting surfaces to air and subsequent oxidation.

Another object is to provide a fluid-cooled terminal for a flexible conductor wherein the cooling tube has a plurality of courses or passes within the terminal shell, for example, being of approximately U-shaped form so as to increase the area of thermal contact with the conductor strands and consequently to increase its cooling capacity.

Other objects and advantages of the present invention will become apparent from the following description of the accompanying drawings, wherein:

FIGURE 1 is a diagrammatic cross section through a cylindrical terminal shell with the end of a flexible conductor and a cooling tube inserted therein prior to de-' formation thereof;

FIG. 2 is a top plan view of a fluid-cooled terminal for a flexible conductor in accordance with the present invention;

FIG. 3 is a side elevation of the fluid-cooled terminal of FIG. 2;

FIG. 4 is a vertical cross section taken substantially along the line 4-4 of FIG. 3;

shell 12. The strands of the ropes 12 FIG. 5 is a top plan view of a fluid-cooled terminal provided with a totally enclosed cooling tube; and

FIG. 6 is a cross-sectional view taken substantially along the line 6-6 of FIG. 5.

A fluid-cooled terminal 10 in accordance with the present invention is shown in operative association with a flexible electrical conductor 11 suitable for use as a welding cable. The flexible conductor 11, for the major end portion 22 of the flexible conductor 11 is firmly compressed within the chamber 21 with the strands thereof closely compacted around the cooling tube 14. A bolt hole 24 extends through the upper wall 16, end portion 22 of the flexible conductor 11, and the lower wall 18 for the reception of a clamping bolt (not shown) by which the terminal It) is secured to, for example, a conventional welding machine or transformer (not shown).

The two-pass cooling tube 14 has a substantially U- shaped cross section defined by a pair of spaced parallel leg or heat exchangeportions 28 and 29 connected by a bight portion 30. The leg portions 23 and 29 are provided with transversely extending end portions 31 and 32, respectively, having threaded portions 33 and 34 thereon, respectively, to facilitate connection of the tube 14 to a source of cooling fluid (not shown).

Referring to FIG. 1, the terminal 10 is fabricated by inserting the end portion 22 of the flexible conductor 11 in a cylindrical copper or brass tube 36 along with the cooling tube 14. This assembly is then transferred to a die cavity 38 of a die 39 having an internal configuration corresponding to the ultimate configuration of the terminal 10. The die cavity 38 has a bottom wall 40 and side Walls 41 and 42 which, respectively, reproduce the bottom wall 18 and side walls 19 and 20 of the terminal 10. The upper Wall 16 of t e terminal 10 is produced by the lower end wall 44 of a punch 45 which is associated with the die 39.

As the punch 45 passes downwardly into the die cavity 38, it deforms the shell 36 to an elongated rectangular configuration. At the same time, the strands of the ropes 12 of the flexible conductor 11 are rearranged and compacted around the periphery of the cooling tube 14 protecting the tube 14 from collapse and deforming slightly so as to provide good electrical and mechanical contact between the strands and the tube 14 and terminal are coined into what is effectively a solid terminal structure 10, which precludes oxidation of the contacting surfaces thereof with its consequent increase in electrical resistance. The bolt hole 24 is then drilled through the upper wall 16.. the compacted end portion 22 of the flexible conductor 11, and the lower wall 18, completing the terminal 10. The U-shaped configuration of the cooling tube 14 permits the hole 24 to be drilled centrally of the terminal 10.

Referring to FIGS. 5 and 6, an elongated, fluid-cooled terminal 50 is shown operatively related with a flexible conductor 51. The terminal 50 comprises a cooling tube 52 of U-shaped cross section defined by a pair of spaced, generally parallel, longitudinally extending leg or heat exchange portions 54 and 55, and a bight portion 56. The cooling tube 52 is disposed within a shell 58, of electrically conductive material, preferably copper or brass, in close heat exchanging relationship with the compacted strands of an end portion 59 of the flexible conductor 51. The leg portions 54 and 55 of the tube 52 are provided with transversely extending end portions 60 and '61, respectively, having threaded portions 62 and 63 thereon, respectively, to facilitate connection of the tube 52 to a source of cooling fluid (not shown). A hole 64 disposed centrally of the leg portions 54 and 55 and bight portion 56 extends through the terminal 50 to facilitate the bolted connection thereof to an electrical conductor (not shown).

The flexible conductor 51 is provided with an insulating jacket 65 having apertures 66 and 68 therein for the acceptance of the end portions 60 and 61, respectively, of the tube 52.

The shell 58 'of the terminal 50 totally encloses the leg portions 54, 55, and the bight portion 56 of the tube 52 so as to provide for maximum heat transfer between the compacted strands of the flexible conductor 51 and the cooling fluid carried within the tube 52. Also, by totally enclosing the tube 52 within the shell 58, the bight portion 56 of the tube 52 is protected against damage.

While it will be apparent that the embodiments of the invention herein disclosed are well calculated to fulfill the objects of the invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

'1. An air-cooled welding cable and liquid-cooled terminal unit comprising an elongated tubular terminal member having open opposite ends and having a chamber .extending longitudinally therethrough from end to end, an approximately U-shaped cooling liquid tube having substantially parallel longitudinal portions extending lengthwise through said chamber and a bridge portion disposed transversely of said terminal member and interconnecting said longitudinal portions near one end of said terminal member, said cooling tube having end portions projecting outwardly from the other end of said terminal member, said end portions having pipe coupling portions thereon adapted to be coupled to cooling liquid supply and discharge pipes respectively, and a welding cable composed of minute wire strands, one end of said cable being tightly secured in said chamber alongside said longitudinal tube portions with the strands thereof snugly engaging said tube terminal member and tube, said terminal member being disposed in compressively stressed relationship with said cable end and said tube.

2. An air-cooled welding cable and liquid-cooled terminal unit according to claim 1 wherein said outwardly projecting end portions of said cooling tube are bent transversely to said parallel longitudinal portions in directions away from said cable.

3. A fluid-cooled terminal for a flexible electrical conductor comprising an electrically conductive housing, a cooling fluid tube having an approximately U-shaped section the legs of which extend longitudinally through said housing in parallel relation and extend from the housing at one end, a stranded flexible electrical conductor having its end extending into said housing and compacted about said cooling fluid tube, said housing being disposed in compressibly stressed relationship with said cable end and tube assembly to form a substantially homogeneous structure with respect to heat and electrical conductivity, and means on said terminal for electrically connecting said flexible conductor in an electrical circuit.

References Cited in the file of this patent UNITED STATES PATENTS 1,292,716 Cox Jan. 2, 1919 1,674,829 La Bean June 26, 1928 2,222,574 Robertson Nov. 19, 1940 2,433,588 Wreford Dec. 30; 1947 2,480,803 Wreford Aug. 30, 1949 2,686,215 Fondiller Aug. 10, 1954 2,831,911 Winters Apr. 22, 1958 FOREIGN PATENTS 504,377 Canada July 13, 1954 

